A major performance limitation of electrical interconnections is inductive noise encountered when one interconnects high-speed, high pin-out integrated circuit (IC) chips having many drivers that switch simultaneously. For example, an array size of 256.times.256 can be fabricated on a single chip, however such large arrays are impractical because of the inductive noise generated by the line drivers driving the output leads of the chip. When a large number of drivers are active simultaneously, a substantial transient current passes through the inductance of the ground and power distribution systems, causing a noise spike to emerge on the power and ground lines. The resulting fluctuation of the power and ground voltage levels can cause false switching of devices with an accompanying error or loss of data.
Several techniques have been proposed for reducing inductive noise. At the circuit level, the noise can be reduced by staggering the switching times of the drivers. The staggering of the switching times, however, has the drawbacks of decreased switching speed and increased complexity of clock distribution. At the architectural level, techniques such as the design rule, called the Simultaneous Switching Rule (SSR) can be used to limit the number of drivers that need to be activated simultaneously in a chip. The SSR is a linear inequality that restricts the number of driver circuits allowed to switch simultaneously, so that no logic errors will occur. The restrictions imposed by the SSR however translate into machine cycle time penalties and affect the performance rating of a machine. Thus, a compromise must be made when developing the SSR in order to minimize the impact on the machine cycle.
Other approaches also used to reduce inductive noise include chip attachment technologies such as solder bump leads and tape automated bonding (TAB). However, the use of these techniques is substantially more expensive than conventional wire bonding and has not achieved the reliability of wire bond technology. Since wire bonding is a mature and reliable technology with a large capital investment, it is desirable to reduce the inductive noise and retain the wire bond technology.